Nanomaterial Inhalational Exposure and Potential Health Effects Engineered nanomaterials (ENMs) are an emerging category of materials that are finding increasing use in the areas of imaging, electronics and therapeutics; however, they are already part of a widening number of products that are commonly used such as computer chips, cosmetics, clothing and dietary supplements. Even though these ENMs may prove to be beneficial, there have been concerns raised regarding their potential health risks. Although these particles have been studied for the last few decades, only recently has the potential toxicity of ENMs been researched in a serious way. This issue of toxicity has been recently highlighted by the case report of 7 female factory workers exposed to nanoparticles during their work for 5-13 months who developed lung damage with pulmonary fibrosis and inflammation^, although there may have been other factors involved in these unfortunate cases. People that may be exposed to ENMs include workers, consumers and the general public through a number of ways that include by skin or by the gastrointestinal route or through the eyes, but the inhaled route remains potentially the most important one. The inhaled route is also an important one for a number of applications for ENMs including imaging agents, gene therapy and therapeutic drug delivery to infected or tumour sites.